1. Field of the Invention
The present invention relates to an apparatus and method for welding a stud onto the end of a broken-off stud. This invention also relates to the stud which is used in the welding process. More particularly, the present invention relates to a welding (stud) gun, the overall welding process, and the stud which is used in the welding process.
2. The Prior Art
The problem which is addressed by the present invention is broadly in the automotive field. More precisely, however, the problem relates to the attachment of an exhaust pipe section to the exhaust manifold of an automobile engine. In this regard, the manifold is normally provided with a circular flange against which the enlarged end of an exhaust pipe section is adapted to fit. A gasket or washer is generally interposed between the enlarged end of the exhaust pipe section and the seat on the flange. A collar is generally received on the exhaust pipe section on the opposite side of the enlarged portion from the manifold flange. Normally, two to four studs which are threaded into the manifold flange extend outwardly from the manifold flange and pass through an equal number of holes in the collar. Threaded nuts are placed on the threaded ends of the studs which project through the collar and are thereafter tightened so as to draw the collar close to the manifold to produce a tight connection between the end of the exhaust pipe and the manifold.
Occasionally, when one is replacing an exhaust pipe section, he will discover that one of the studs has been broken off, generally adjacent the surface of the flange or sometimes even internally within the flange. One of the practices in the past has been to remove the broken stud so as to put a new stud in place. However, this removal generally involves drilling a hole into the broken stud and using an "easy-out" or some other suitable device to remove the broken stud. This method of removing the broken stud is not only difficult, but quite time-consuming. As an alternative to removing the stud, one company (Nickson Industries of Plainville, Connecticut) proposes the use of a C-clamp which is placed over the broken stud and becomes a permanent connection between the exhaust pipe and the manifold. However, as one might visualize, continued vibration of the automobile over the roadway will cause the C-clamp to come loose and the repair is comprised.
With applicant's invention in mind, a search was made in the prior art. No references were found which were considered sufficiently pertinent to require any comment. However, the following U.S. Patents were uncovered in the search:
______________________________________ 2,256,480 2,429,967 2,475,907 2,482,910 2,539,136 2,563,107 2,635,403 2,760,797 2,768,794 2,787,943 2,795,176 2,817,003 2,860,230 3,021,420 3,095,951 3,204,083 3,279,047 3,352,189 3,363,084 3,408,472 3,409,088 3,439,567 3,487,733 3,504,598 3,522,409 3,641,310 3,732,023 3,826,893 3,892,942 3,952,811 4,045,643 4,137,681 4,138,909 4,458,763 ______________________________________